What Is Peripheral Arterial Disease?

Peripheral arterial disease (P.A.D.) is a disease in which plaque (plak) builds up in the arteries that carry blood to your head, organs, and limbs. Plaque is made up of fat, cholesterol, calcium, fibrous tissue, and other substances in the blood.

When plaque builds up in the body's arteries, the condition is called atherosclerosis (ATH-er-o-skler-O-sis). Over time, plaque can harden and narrow the arteries. This limits the flow of oxygen-rich blood to your organs and other parts of your body.

P.A.D. usually affects the arteries in the legs, but it also can affect the arteries that carry blood from your heart to your head, arms, kidneys, and stomach. This article focuses on P.A.D. that affects blood flow to the legs.

NHLBI

      Normal Artery and Artery With Plaque Buildup

The illustration shows how P.A.D. can affect arteries in the legs. Figure A shows a normal artery with normal blood flow. The inset image shows a cross-section of the normal artery. Figure B shows an artery with plaque buildup that's partially blocking blood flow. The inset image shows a cross-section of the narrowed artery.

     Overview

Blocked blood flow to your legs can cause pain and numbness. It also can raise your risk of getting an infection in the affected limbs. Your body may have a hard time fighting the infection.

If severe enough, blocked blood flow can cause gangrene (tissue death). In very serious cases, this can lead to leg amputation.

If you have leg pain when you walk or climb stairs, talk with your doctor. Sometimes older people think that leg pain is just a symptom of aging. However, the cause of the pain could be P.A.D. Tell your doctor if you're feeling pain in your legs and discuss whether you should be tested for P.A.D.

Smoking is the main risk factor for P.A.D. If you smoke or have a history of smoking, your risk of P.A.D. increases up to four times. Other factors, such as age and having certain diseases or conditions, also increase your risk of P.A.D.

     Outlook

P.A.D. increases your risk of coronary heart disease (CHD; also called coronary artery disease), heart attack, stroke, and transient ischemic attack  ("mini-stroke"). If you have CHD, you have a 1 in 3 chance of having blocked leg arteries.

Although P.A.D. is serious, it's treatable. If you have the disease, see your doctor regularly and treat the underlying atherosclerosis.

P.A.D. treatment may slow or stop disease progress and reduce the risk of complications. Treatments include lifestyle changes, medicines, and surgery or procedures. Researchers continue to explore new therapies for P.A.D.


     Other Names for Peripheral Arterial Disease

  • Atherosclerotic peripheral arterial disease
  • Claudication (klaw-dih-KA-shen)
  • Hardening of the arteries
  • Leg cramps from poor circulation
  • Peripheral vascular disease
  • Poor circulation
  • Vascular disease

     What Causes Peripheral Arterial Disease?

The most common cause of peripheral arterial disease (P.A.D.) is atherosclerosis
Atherosclerosis is a disease in which plaque builds up in your arteries. The exact cause of atherosclerosis isn't known.
The disease may start if certain factors damage the inner layers of the arteries. These factors include:
  • Smoking
  • High amounts of certain fats and cholesterol in the blood
  • High blood pressure
  • High amounts of sugar in the blood due to insulin resistance or diabetes           

When damage occurs, your body starts a healing process. The healing may cause plaque to build up where the arteries are damaged.

Eventually, a section of plaque can rupture (break open), causing a blood clot to form at the site. The buildup of plaque or blood clots can severely narrow or block the arteries and limit the flow of oxygen-rich blood to your body.

Who Is at Risk for Peripheral Arterial Disease?

Peripheral arterial disease (P.A.D.) affects millions of people in the United States. The disease is more common in African Americans than any other racial or ethnic group.

The major risk factors for P.A.D. are smoking, older age, and having certain diseases or conditions.

     Smoking

Smoking is the main risk factor for P.A.D. Your risk of P.A.D. increases four times if you smoke or have a history of smoking.

On average, people who smoke and develop P.A.D. have symptoms 10 years earlier than people who don't smoke and develop P.A.D.

Quitting smoking slows the progress of P.A.D. Smoking even one or two cigarettes a day can interfere with P.A.D. treatments. People who smoke and people who have diabetes  are at highest risk for P.A.D. complications, such as gangrene (tissue death) in the leg from decreased blood flow.

     Older Age

Older age also is a risk factor for P.A.D. Plaque builds up in your arteries as you age. About 1 in every 20 Americans over the age of 50 has P.A.D. The risk continues to rise as you get older.

Older age combined with other risk factors, such as smoking or diabetes, also puts you at higher risk for P.A.D.

     Diseases and Conditions

Many diseases and conditions can raise your risk of P.A.D., including:

  • Diabetes. About 1 in 3 people older than 50 who has diabetes also has P.A.D.
  • High blood pressure or a family history of it.
  • High blood cholesterol or a family history of it.
  • Coronary heart disease (CHD) or a family history of it.
  • Stroke or a family history of it.
  • Metabolic syndrome (a group of risk factors that raise your risk of CHD and other health problems, such as P.A.D., stroke, and diabetes). 

     What Are the Signs and Symptoms of Peripheral Arterial Disease?

Many people who have peripheral arterial disease (P.A.D.) don't have any signs or symptoms. Others may have many signs and symptoms.

Even if you don't have signs or symptoms, ask your doctor whether you should get checked for P.A.D. if you're:

  • Aged 70 or older
  • Aged 50 or older and have a history of smoking or diabetes 
  • Younger than 50 and have diabetes and one or morerisk factors for atherosclerosis

     Intermittent Claudication

People who have P.A.D. may have symptoms when walking or climbing stairs. These symptoms may include pain, numbness, aching, or heaviness in the leg muscles.

Symptoms also may include cramping in the affected leg(s) and in the buttocks, thighs, calves, and feet. Symptoms may ease after resting.

These symptoms are called intermittent claudication. During physical activity, your muscles need increased blood flow. If your blood vessels are narrowed or blocked, your muscles won't get enough blood, which will lead to symptoms. When resting, the muscles need less blood flow, so the symptoms will go away.

About 10 percent of people who have P.A.D. have claudication. This symptom is more likely in people who also have atherosclerosis in other arteries.

     Other Signs and Symptoms

Other signs and symptoms of P.A.D. include:

  • Weak or absent pulses in the legs or feet
  • Sores or wounds on the toes, feet, or legs that heal slowly, poorly, or not at all
  • A pale or bluish color to the skin
  • A lower temperature in one leg compared to the other leg
  • Poor nail growth on the toes and decreased hair growth on the legs
  • Erectile dysfunction, especially among men who have diabetes

How Is Peripheral Arterial Disease Diagnosed?

Peripheral arterial disease (P.A.D.) is diagnosed based on your medical and family histories, a physical exam, and test results.

P.A.D. often is diagnosed after symptoms are reported. A correct diagnosis is important because people who have P.A.D. are at higher risk for coronary heart disease (CHD), heart attack, stroke, and transient ischemic attack  ("mini-stroke"). If you have P.A.D., your doctor also may want to check for signs of these diseases and conditions.

     Specialists Involved

Primary care doctors, such as internists and family doctors, may treat people who have mild P.A.D. For more advanced P.A.D., a vascular specialist may be involved. This is a doctor who specializes in treating blood vessel diseases and conditions.

A cardiologist also may be involved in treating people who have P.A.D. Cardiologists treat heart problems, such as CHD and heart attack, which often affect people who have P.A.D.

     Medical and Family Histories

Your doctor may ask:

  • Whether you have any risk factors for P.A.D. For example, he or she may ask whether you smoke or have diabetes.
  • About your symptoms, including any symptoms that occur when walking, exercising, sitting, standing, or climbing.
  • About your diet.
  • About any medicines you take, including prescription and over-the-counter medicines.
  • Whether anyone in your family has a history of heart or blood vessel diseases.

     Physical Exam

During the physical exam, your doctor will look for signs of P.A.D. He or she may check the blood flow in your legs or feet to see whether you have weak or absent pulses.

Your doctor also may check the pulses in your leg arteries for an abnormal whooshing sound called a bruit (broo-E). He or she can hear this sound with a stethoscope. A bruit may be a warning sign of a narrowed or blocked artery.

Your doctor may compare blood pressure between your limbs to see whether the pressure is lower in the affected limb. He or she also may check for poor wound healing or any changes in your hair, skin, or nails that may be signs of P.A.D.

     Diagnostic Tests

Ankle-Brachial Index

A simple test called an ankle-brachial index (ABI) often is used to diagnose P.A.D. The ABI compares blood pressure in your ankle to blood pressure in your arm. This test shows how well blood is flowing in your limbs.

ABI can show whether P.A.D. is affecting your limbs, but it won't show which blood vessels are narrowed or blocked.

A normal ABI result is 1.0 or greater (with a range of 0.90 to 1.30). The test takes about 10 to 15 minutes to measure both arms and both ankles. This test may be done yearly to see whether P.A.D. is getting worse.

Ankle-Brachial Index

The illustration shows the ankle-brachial index test. The test compares blood pressure in the ankle to blood pressure in the arm. As the blood pressure cuff deflates, the blood pressure in the arteries is recorded.

Doppler Ultrasound

A Doppler ultrasound looks at blood flow in the major arteries and veins in the limbs. During this test, a handheld device is placed on your body and passed back and forth over the affected area. A computer converts sound waves into a picture of blood flow in the arteries and veins.

The results of this test can show whether a blood vessel is blocked. The results also can help show the severity of P.A.D.

Treadmill Test

A treadmill test can show the severity of symptoms and the level of exercise that brings them on. You'll walk on a treadmill for this test. This shows whether you have any problems during normal walking.

You may have an ABI test before and after the treadmill test. This will help compare blood flow in your arms and legs before and after exercise.

Magnetic Resonance Angiogram

A magnetic resonance angiogram (MRA) uses magnetic and radio wave energy to take pictures of your blood vessels. This test is a type of magnetic resonance imaging  (MRI).

An MRA can show the location and severity of a blocked blood vessel. If you have a pacemaker, man-made joint, stent, surgical clips, mechanical heart valve, or other metallic devices in your body, you might not be able to have an MRA. Ask your doctor whether an MRA is an option for you.

Arteriogram

An arteriogram provides a "road map" of the arteries. Doctors use this test to find the exact location of a blocked artery.

For this test, dye is injected through a needle or catheter (tube) into one of your arteries. This may make you feel mildly flushed. After the dye is injected, an x ray is taken. The x ray can show the location, type, and extent of the blockage in the artery.

Some doctors use a newer method of arteriogram that uses tiny ultrasound cameras. These cameras take pictures of the insides of the blood vessels. This method is called intravascular ultrasound.

Blood Tests

Your doctor may recommend blood tests to check for P.A.D. risk factors. For example, blood tests can help diagnose conditions such as diabetes  and high blood cholesterol.
source: NHLBI / updated November 2011
see also: